Coordination of concrete delivery and placement

Abstract

To provide a method for coordinating the concrete delivery and placement.SOLUTION: Described are a method and system for coordinating the delivery and placement of concrete loads at a job site, and more particularly for coordinating a curing time value or value range of the concrete loads, thereby to facilitate finishing or other concrete placement operations. In exemplary embodiments, the coordination may be made based on an assessment of previously placed concrete loads. The curing time value or value range of the concrete can be monitored and coordinated to achieve desired properties during installation and / or in its cured state.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The inventors are Nathan TREGGER, Mark ROBERTS, Jason STRAKA, Elise BERODIER, Greg AUSTIN, Robert HOOPES.

[0002] The present invention relates to concrete construction processes and systems, and more particularly to coordinating cure time values or ranges of values, such as workability or compressive strength windows, of concrete loads delivered and placed at a job site.

Background Art

[0003] Batch processing of concrete mixture loads typically involves introducing cement, aggregates, water, and optional chemical admixtures into the rotating mixer drum of a ready-mix truck, where the components are uniformly mixed together and transported to the job site where the concrete mixture is to be placed.

[0004] The term "placement" or "pour" may hereinafter be used to refer to the various means of transporting plastic concrete from the truck drum to its final placement at the job site. This includes steps of discharging the concrete from the drum onto a chute that can flow or be pushed into a space or framework for slabs, roads, foundations, walls, or other uses, pumping the concrete to a location within a high-rise building above ground level, spraying the concrete onto a surface such as a foundation, wall, or tunnel surface, or depositing one concrete mass on top of a previously deposited concrete mass in a 3D printing process or the like.

[0005] For example, when concrete is used to create a horizontal slab, floor, deck, pavement, or road, the concrete has a relatively narrow period or window in which it can be "finished." Finishing includes various steps such as flattening and smoothing the surface (troweling) to ensure its durability. The construction site supervisor (or manager) desires a sense of the "initial set time," or put another way, wants to predict the moment when the poured concrete first develops the strength such that it is workable (i.e., the ability to be smoothed or moved to a desired location) and the surface finishing process can be started. The supervisor will also likely want a sense of the "final set time" or the moment when the concrete loses its workability and can no longer be finished. This is particularly relevant when the supervisor does not have construction workers for each poured concrete load and has to operate with limited resources within short time intervals.

[0006] The determination of whether the poured concrete can be finished (smoothed) is often done by judging the "shine of the water" on the concrete surface, but this test is subjective and is often misinterpreted due to the need to finish quickly. Dust problems, flaky surface defects, and large-scale cracking make it difficult to determine when the concrete surface is ready to be finished. The usual "footprint" tests for determining the initial set time or final set time are subjective and error-prone.

[0007] When concrete is used in vertical applications such as walls, columns, or support structures (e.g., high-rise buildings), the supervisor's concerns may focus on various aspects of the setting time. When the concrete starts to exhibit internal cohesion, which ultimately leads to increased rigidity and final hardness Understanding this can help the applicator better understand the appropriate rate at which the concrete can be pumped or injected to avoid rupture of the formwork. By understanding when the concrete begins to acquire compressive strength, the supervisor can determine how soon the formwork can be removed, or can decide how soon the next concrete section can be poured on top of the previously poured concrete section. Thus, the supervisor may want to better understand the early hardening time as well as the nature of the later hardening time (e.g., the compressive strength of the concrete after 1, 3, 7, or 28 days of batching).

[0008] The present invention focuses on the determination of one or more hardening time values or ranges of values, such as the early hardening time, the final hardening time, and / or two or more hardening time values. This can include the start and / or end of the workability / finishability window of plastic (workable) concrete, which can also include strength values for hardened (unworkable) concrete, such as at 4 hours, or after 1, 3, 7, or 28 days, or other ages, of compressive strength.

[0009] The contractor at the construction site may want to consider one hardening time value, such as the final hardening time (before which the concrete must be finished before it hardens), or, as another example, a range of hardening time values that includes both the early hardening time (after which finishing can be started) and the final hardening time (before which finishing must be completed).

[0010] In FIG. 1, the inventors illustrate a common problem using three exemplary timelines representing three delivery trucks (designated 10, 12, and 14) that carry concrete loads within a mixer drum. Each load has different hydration behavior. Each load has a batch time (B) that begins at a batch plant and different placement times (P) when the load is discharged at the job site. As shown by the dashed rectangles, the problem is caused by different hardening time values that define different time spans or ranges, e.g., different finish start times (designated Fs) and different finish completion times (designated Fc). As shown in FIG. 1, the concrete poured from trucks 10 and 14 has similar placement (P) times. The finish workers can finish the poured load 10 before working on the poured load 14 because the Fc of load 10 ends before the Fs of load 14 begins. However, load 12 has a later placement time and finish start time (Fs) compared to the start time of load 14. Load 12 also has a finish completion time (Fc) that occurs earlier compared to the finish time of load 14. Thus, unregulated hardening time behavior of concrete placement makes the finish process at the job site very complex.

[0011] The concrete industry attempts to organize concrete deliveries by batch loading trucks at hardening intervals (e.g., every 15 minutes), but the basic assumption that trucks arrive at the job site at similarly spaced intervals is often difficult. For example, in the move from the batch plant (B) to the placement site (P), trucks can be delayed by traffic and job site congestion, pump failures at the site, admixture dosing errors, temperature changes that affect concrete hydration at the job site, and other problems. Inconsistencies in concrete mixtures such as different batch weights and mix designs (e.g., loads may contain return concrete) can affect the hydration behavior and cause variations in hardening time values (e.g., Fs, Fc).

[0012] As a result of uncontrolled setting time values or ranges of values in the concrete being delivered, costly and time-consuming problems are caused, such as concrete parts that had to be removed and replaced because they did not finish within the applicable time.

Summary of the Invention

[0013] In overcoming the above problems, the present invention preferably includes a step of adjusting one or more assigned setting time values or ranges of values of a concrete mixture load being delivered to the site, based on an evaluation of the concrete previously delivered and placed at the work site, enabling the concrete being delivered to have an adjusted setting time value or range of values. Thereby, the properties of the concrete can be controlled.

[0014] As shown in FIG. 2, three concrete loads (B) are delivered to the work site (P) where they are located by trucks (16, 18, 20) in accordance with an exemplary embodiment of the present invention. In this example, the rheology and hydration rate behavior of the concrete mixture are monitored and adjusted so that the range of set times after placement does not overlap. Although there may be some overlap (since some of the finishing workers can start moving from a section of the injected concrete to work in the next section), for the purpose of simplifying this figure, the start time (Fs) and finish time (Fc) of finishing for the three injected concrete loads 16 / 18 / 20 are shown as not overlapping. For example, if there are only a minimum number of crew workers nearby to finish the placed concrete, the Fs and Fc time events can be spaced far enough apart so that each injected section (e.g., 16 or 18) can be finished before the crew moves on to the next injected section (e.g., 18 or 20). Also, there may be a slight overlap in the range of set time values, such as when a supervisor allows some of the finishing crew workers to move from one injected concrete section to another while completing the necessary finishing before hardening, but the goal is to avoid multiple concrete loads having matching set times (e.g., 12 / 14 in FIG. 1) when there are not enough workers to complete the finishing stage.

[0015] Thus, the concept of adjusting the set time value or range of values of the present invention starts with the use of an automatic concrete rheology (e.g., slump) management system for individual fresh concrete delivery trucks, and the system is controlled by a processor that enables the input or calculation of a set time value (e.g., initial set time) or range of values (e.g., initial and final set time values, and / or strength levels) (e.g., by the processor of a slump monitoring system mounted on the concrete delivery truck).

[0016] The present invention also allows for adjustment of the initial set time based on concrete rheology data, such as from a site supervisor, or based on information from other concrete delivery trucks monitoring various concrete loads being delivered to the job site, or perhaps based on sensor data obtained from sensors placed above or on the surface of or embedded within the placed concrete (or a combination thereof).

[0017] For purposes of this invention, the concept of a "setting time value or range of values" can refer to any number of activities including (a) the start of finishing, (b) the completion of finishing, (c) the removal of the framework or form from the concrete (i.e., after hardening), (d) the allowing of foot or vehicular traffic over the concrete, (e) the pouring of more concrete on top of the poured concrete, or (f) other pouring site activities such as prestressing concrete mechanism adjustments. Setting time values ​​are presumed to reflect the moment the concrete load is loaded or mixed at the batching plant or is reconditioned (in case of return from a different job site or from a different pouring location at the same job site) and new concrete is batched on top of the returned concrete load. In other words, setting time values ​​or ranges of values ​​can refer to any of a number of placement time time events depending on the application. or even post-placement properties such as concrete compressive strength at various ages.

[0018] Thus, an exemplary method for coordinating delivery of concrete of the present invention includes: (A) providing at least two delivery trucks, each having a mixer drum containing a concrete load and a processor controlled system for monitoring the rheology (e.g., slump, slump flow, yield stress) and at least one set time value or range of values ​​(e.g., initial set time, final set time, compressive strength or a mixture of these values) of the concrete load in the drum, wherein the processor: (i) Accessing at least one stored setting time value or range of values assigned to the concrete loaded in the mixer drum for delivery to the job site; (ii) Calculating at least one current setting time value or range of values of the load based on hydration monitored over time; (iii) Comparing the at least one stored setting time value or range of values with the at least one calculated current setting time value or range of values; Steps programmed to perform functions including; (B) Adjusting the current setting time value(s) or range(s) of values by introducing an accelerating agent, a retarding agent, or a mixture thereof into at least one of the at least two delivery truck concrete loads to effect the sequential placement, finishing, stripping, form removal, or compressive strength stages of the concrete load injected from at least two delivery trucks; Including.

[0019] In further exemplary embodiments, the stored or current curing time value can include an initial curing time (after which finishing can be started), a final curing time (before which finishing needs to be completed), and possibly even a range of curing time values (e.g., defined by both the initial and final curing times), and can also include other placement events (e.g., the age of one or more concretes, e.g., the strength development of the placed concrete at 4 hours, 4 days, or other ages from the time of batching). Again, there can be some overlap with respect to the workability window (e.g., the end time of a previous placement can occur after the start time of a subsequent placement). The stored or current curing time value can be established, for example, by using a commercially available slump monitoring system mounted on a delivery truck and preferably monitoring the temperature change of the concrete over time at a given concrete slump. The inventors envision that adjustment of the current curing time value or range of values of a concrete load can be achieved by using such commercially available monitoring systems (e.g., the VERIFI® Monitoring Systems of GCP Applied Technologies Inc. of Cambridge, Massachusetts) to monitor the dosage of an accelerator, a retarder, or a mixture thereof. Further, in further exemplary embodiments, the present invention facilitates rerouting of a complete or partial delivery truck load from a first job site to another job site for delivering a complete or partial load, so the first job site may not be the final "placement site".

[0020] In further exemplary embodiments, monitoring the hydration of each concrete load over time can be done in several ways. For example, the temperature of the concrete load is measured over time and can be considered along with the batch quantity (including the load size at the batch plant and any additional water or admixtures added at any point in time, plus the age of the concrete).

[0021] The present invention also provides a method for monitoring the hardening time conditions of a plurality of concrete placements , the method comprising: Moving at least one aerial drone having at least one sensor (e.g., a sensor selected from optical, infrared, acoustic, radio wave, microwave, electrical resistivity, capacitance, and ultrasonic sensors) over a plurality of concrete placement locations at a work site to monitor the hydration of the placed concrete over time to obtain a data signal indicative of hydration; Comparing the obtained data signal with previously stored data signals to obtain a hardening time value or range of values correlated with the hydration data over time obtained from the at least one sensor; Generating a drawing or map of the plurality of concrete placement locations together with the hardening time value or range of values, or a proposed sequence priority based on the hardening time value or range of values, thereby providing an indication of an arrangement suitable for sequential processing with respect to (a) the start of finishing, (b) the completion of finishing, (c) the step of removing the formwork or mold from the concrete, (d) the step of permitting pedestrian or vehicle passage on the concrete, (e) the step of releasing a tensioned cable from a jack (e.g., for use in prestressed concrete applications), (f) the anchoring or grouting of the cable after tensioning (e.g., for concrete after tensioning), or (g) the step of pouring additional concrete on top of the previously poured concrete; comprising.

[0022] Further advantages and features of the present invention are described in more detail below.

Brief Description of the Drawings

[0023] The advantages and features of the present invention can be more easily understood by considering the following written description of the preferred embodiments in conjunction with the drawings.

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DETAILED DESCRIPTION OF THE INVENTION

[0024] As used herein, various devices and components may be described as "comprising" other components. The terms "comprise(s)", "include(s)", "having", "has", "can", "contain(s)" and variations thereof as used herein are intended to be transitional phrases, terms or words without limitation that do not exclude the possibility of additional components.

[0025] The term "concrete" typically refers to a mixture of cement (which often includes supplementary cementitious materials such as limestone, fly ash, ground granulated blast furnace slag and other pozzolanic materials) and aggregates (e.g., fine aggregates such as sand, coarse aggregates such as gravel), and optionally one or more chemical admixtures (e.g., plasticizers to enhance workability, accelerators, retarders, air-entraining agents, air-entraining inhibitors, plastic shrinkage reducing admixtures, corrosion inhibitors (for reinforcing steel) to modify the concrete in its plastic or hardened state). Concrete is considered a hydratable material in that the addition of water to the mixture of cement and aggregates initiates the hardening reaction.

[0026] The term "cement" includes hydratable cements such as Portland cement produced by grinding clinker consisting of hydraulic calcium silicates, aluminates and aluminoferrites, and one or more forms of calcium sulfate (e.g., gypsum) as a grinding additive. Typically, Portland cement is combined with one or more supplementary cementitious materials such as fly ash, ground granulated blast furnace slag, limestone, natural pozzolan, or mixtures thereof, and provided as a blend, all of which bind the aggregates together to form concrete. Thus, "cement" and "cement binder" may also include supplementary cementitious materials interground with Portland cement during manufacture.

[0027] The term "concrete delivery truck(s)" is also known as a fresh concrete truck(s) and means a vehicle having a rotatable mixer drum with a non-vertical axis of rotation, and shall refer to such. Such a mixer drum typically has at least one blade or fin attached to the inner wall of the drum and arranged spirally around the axis of rotation, with rotation of the drum in one direction pushing the concrete components towards the closed end of the drum (thus, in the mixing or loading mode), while rotation in the opposite direction discharges the material through the open end of the drum (thus, in the pouring or discharging mode).

[0028] The phrases "batch time" or "batch processing time" are designated as "B" in FIGS. 1 and 2 and are used, for example, to refer to various events including (a) the time when the truck begins to receive into the mixer drum concrete or specific mixing components for manufacturing concrete (e.g., cement, aggregates, water, optional chemical admixtures), (b) the time when one or more chemical admixtures (e.g., superplasticizer, set retarder, set accelerator, or mixtures thereof) are added to the mixer drum containing the concrete or concrete components, (c) the time when the materials are mixed together in the mixer drum and are determined to be uniformly mixed (e.g., can be determined by verifying that the slump sensor readings are relatively constant over a predetermined number of drum rotations), or (d) the time when the truck exits the batch plant.

[0029] For example, a particular batch plant can typically indicate the time when the components were introduced into the mixer drum, which can be documented or stored on an electronic or paper batch ticket, and when an electronic batch ticket is issued, the time can be transmitted to the dispatch center of the delivery truck loaded with the concrete and / or an automatic slump monitoring system, which can be used to determine the set time value or range of values for a particular load.

[0030] The term "pour" means and refers to the time when all or a partial load of concrete is discharged, sprayed, or deposited at the final placement location at the job site. Multiple pours can occur. For example, an initial pour can be made to check the concrete properties. Adjustments can be made to the concrete that can continue to be poured. Partial pours can occur if the receptacle for receiving the concrete is full or if the load is rejected after checking the concrete properties. In these cases, the concrete can be returned to the batch plant or to another location at the same or a different job site, and as a result, the remaining concrete can be used.

[0031] For purposes of FIGS. 1 and 2, "pour" is designated as "P" and refers to the instant when all or a partial load of concrete is discharged from a delivery truck at the job site. One truck can have multiple pours. For example, an initial pour can be made to check the concrete properties and to allow adjustments to be made to the concrete, so that the remaining portion of a given load can be discharged from the truck to a predetermined location.

[0032] Partial pours can also occur if the framework, form, or pump hopper for receiving the concrete mixture is full. As another example, partial pours can occur if a particular load is not accepted, and the non-accepted concrete can be returned to the batch plant or to another location at the same or a different job site where the remaining concrete is used.

[0033] The meaning of the concept of "set time value or range of values" as used herein and above is It depends on the specific application for a given concrete placement. This concept can include only a single moment (e.g., final set), or can include a period calculated from batch processing (or reconditioning of returned concrete) (e.g., both initial and final set). The set time value or range of values can include the moment or period for any one or more of the following operations: (a) start of finishing, (b) completion of finishing, (c) step of removing formwork from the concrete or removing the concrete from the mold, (d) step of permitting pedestrian or vehicular traffic on the concrete, (e) step of releasing a tensioned cable from a jack (used in prestressed concrete applications), (f) step of anchoring or grouting a cable after tensioning (with respect to the concrete after tensioning), or (g) step of pouring additional concrete on top of previously placed concrete.

[0034] As explained above, for horizontal applications (e.g., placing concrete highways, slabs, floors, etc.), the set time value that is likely to be of interest is the "initial set time", or alternatively, the earliest time (after batch processing or reconditioning of the concrete) at which troweling or other finishing tools can start to push in, level, screed, smooth, or texture the concrete surface (see, e.g., ACI 302.1R-15). When the concrete has become too hard for finishing, this may be referred to as the "final set time", a term that can also be used to denote the point in time at which the formwork or mold can then be removed. See, e.g., ASTM C191-18a, ASTM C266-18, ASTM C807-18, and ASTM C403-16.

[0035] Other hardening time values or ranges of values can, as another example, include an initial hardening time and / or a final hardening time having post-injection concrete properties such as compressive strength. In some highway slab projects, it is desired to achieve a specific compressive strength target (e.g., 400 psi) within a given period (e.g., 4 hours). Again, the hardening time values or ranges of values that may desirably be monitored and adjusted for the concrete load depend on the particular application for which the concrete load is used.

[0036] As another example, in prestressed concrete applications where steel wires, cables, or rods are used to prestress the concrete, the hardening time values or ranges of values can include the earliest time (from batching) for grouting or anchoring the cables into the concrete and / or for releasing the tensioned cables from the jacks.

[0037] As used herein, the terms “assignment” or “input” refer to a hardening time value or range of values input to a processor for monitoring and / or adjusting a concrete load, which can include, for example, a processor-controlled concrete monitoring system that monitors the rheology (e.g., slump or slump flow) of the concrete mixture load contained in a delivery truck drum. As described above, this hardening time value or range of values can be derived from an electronic ticket provided by the concrete batch manufacturer (e.g., many batch plants simply use 15-minute intervals as the batch processing time, whereby the delivery truck is driven under a power supply system that loads cement, sand / gravel, and water into the mixer drum and any chemical admixtures). Alternatively, the hardening time value or range of values can be calculated by an on-board (truck) processor based on rheology (or slump or slump flow) or other factors by the processor.

[0038] The exemplary methods and systems of the present invention may be practiced using an automated slump management (monitoring) system commercialized by GCP Applied Technologies Inc. through its affiliate Verifi, LLC (both of Cambridge, Massachusetts, USA). It is contemplated by the inventors that such concrete monitoring systems can be used to manage slump or other rheological properties (e.g., slump flow, yield stress, viscosity) during the transport and delivery of concrete from a batch plant to a job site where the concrete is placed. Patent documents describe various automated process control concrete monitoring systems. Such systems can be configured and / or programmed to monitor rheology and various other concrete properties and to dispense admixtures into the mix load. See, for example, U.S. Patent Nos. 8,020,431; 8,118,473; 8,311,678; 8,491,717; 8,727,604; 8,764,273; 8,989,905; and U.S. Patent Application Publication Nos. 2009 / 0037026 (from U.S. Patent Application No. 11 / 834,002); 2012 / 0016523 (from U.S. Patent Application No. 14 / 052,289); 2014 / 0104066 (from U.S. Patent Application No. 14 / 052,289); 2014 / 0104972 (from U.S. Patent Application No. 14 / 052,310); 2015 / 160610 (from International Application No. PCT / US2015 / 025054); and 2015073825 (from International Application No. PCT / US2014 / 065709), which are incorporated herein by reference.

[0039] Furthermore, it is contemplated that other sensors such as force sensors (using stress or strain gauges) can be used to monitor the slump of concrete within a truck mixer drum. For example, see U.S. Patent No. 8,848,061 to Berman and U.S. Patent Application Publication No. 2015 / 0051737 (Sensocrete Inc. / GCP Applied Technologies), U.S. Patent No. 9,199,391 to Denis Beaupre et al. (I.B.B. Rheologie Inc.), or U.S. Patent Application Publication No. 2009 / 0171595 to Benegas and International Publication No. 2007 / 060272 Pamphlet.

[0040] An automatic concrete monitoring system is typically used to monitor "slump", but it should be understood that the present invention includes monitoring other rheological parameters such as slump flow, yield stress, viscosity, and other rheological parameters. The specific term "slump" is used for convenience.

[0041] The assigned or input set time value or range of values can be modified by using an automatic concrete monitoring system based on data analyzed by the system processor as described above. Such data can include, for example, data obtained from electronic sensors used at the job site to acquire moisture, humidity, temperature, or other characteristics. The data can also be obtained from a concrete monitoring system used in another (e.g., lead) truck that pre-dispenses concrete at the same pouring site, and such data can include slump, temperature, water content, mix or batch ratio, or other information stored or derived by the on-board monitoring system.

[0042] In various exemplary embodiments, the modification of the assigned or input cure time value can be performed by a management system processor based on sensor data obtained from sensors used to monitor one or more properties of the concrete after the concrete has been placed at the job site (i.e., poured, flowed, screeded, leveled, smoothed, etc.).

[0043] Sensors placed on or in the concrete surface. The inventors envision that one or more movable or portable sensors can be used to monitor the surface of the concrete once the concrete has been placed in position. For example, one or more sensors can be used on an "unmanned aerial vehicle" (UAV) or drone, as further described in the following paragraphs, or can be suspended from a handheld pole, or can be suspended using a cable or pulley assembly that can be moved over a slab, patch, or other segment of the poured concrete. As another example, one or more sensors can be used in a nozzle for spraying, injecting, or depositing concrete (e.g., in shotcrete, concrete injection into mines, concrete deposition in 3D printing processes, etc.). The types of sensors that can be used can be selected from optical, infrared, acoustic, radio wave, microwave, electrical resistivity, capacitance, and ultrasonic sensors, as well as other sensor types, all of which are types of sensors known for measuring the properties of concrete while it is in a plastic state and / or a cured state. Or portable sensors can be used. For example, one or more sensors can be used on an "unmanned aerial vehicle" (UAV) or drone, as further described in the following paragraphs, or can be suspended from a handheld pole, or can be suspended using a cable or pulley assembly that can be moved over a slab, patch, or other segment of the poured concrete. As another example, one or more sensors can be used in a nozzle for spraying, injecting, or depositing concrete (e.g., in shotcrete, concrete injection into mines, concrete deposition in 3D printing processes, etc.). The types of sensors that can be used can be selected from optical, infrared, acoustic, radio wave, microwave, electrical resistivity, capacitance, and ultrasonic sensors, as well as other sensor types, all of which are types of sensors known for measuring the properties of concrete while it is in a plastic state and / or a cured state.

[0044] Sensors on drones. The term "unmanned aerial vehicle" (UAV), or drone, refers to a device that can be flown remotely and carries one or more sensors for monitoring concrete placement at a job site, one or more processors in the cloud, one or more other delivery trucks, and / or one or more portable devices such as smartphones, tablets, or other portable devices at the job site, and a wireless transmitter for sending data signals to a processor such as a processor mounted on a concrete delivery truck that communicates with one or more portable devices. For example, in U.S. Patent No. 8,599,646, Parrot describes using a drone with an ultrasonic ranging device to measure distance and topography without interference from adjacent drone signals. In U.S. Patent Application Publication No. 13 / 998871, Newman describes a data collection system that enables a drone to collect image data, process the data for anomalies, and pair the images with physical locations. U.S. Patent Application Publication No. 14 / 843455 (MetLife) describes the use of a drone for collecting sensor data, converting the data into insurance-related information, and transmitting the data information via wireless communication. There are also improvements that can enable the use of drones in difficult areas. U.S. Patent No. 8,874,283 describes a method for using a drone within a closed space and controlling it regardless of the presence or absence of a line of sight to the drone, which can be advantageous at a construction site.

[0045] In the construction field, drones are mainly used to enable the digitalization and visualization of construction sites (see, for example, Chinese Patent Application Publication No. 104536456). They have been used to capture aerial images that can be presented to contractors or other site planners (see, for example, TREMCO SkyBEAM (trademark) asset mapping). U.S. Patent Application Publication No. 2017 / 0016874 discloses that a drone can collect data signals from sensors embedded in concrete at a construction site.

[0046] Sensors embedded in concrete. In exemplary embodiments of the present invention, embeddable sensors can be used. These are placed within the matrix of the poured concrete or attached to the reinforcing bars before the concrete is poured into a mold or formwork, and transmit data corresponding to the humidity, temperature, hardening, and other properties of the placed concrete via wired or wireless means. For example, embedded sensors have been used in concrete structures for structural monitoring (see, e.g., U.S. Patent No. 4,943,930, U.S. Patent No. 8,913,952), strength development (see, e.g., U.S. Patent No. 7,551,085), humidity measurement (see, e.g., U.S. Patent Application Publication No. 2007 / 0116402), and other applications including corrosion detection (see, e.g., U.S. Patent Application Publication No. 2015 / 0048844). The sensors are even envisioned to be placed inside the plastic concrete contained in a concrete delivery truck, for example, see U.S. Patent Application Publication No. 2015 / 0212061, which is intended to monitor properties such as slump, temperature, and humidity. These sensors can remain in the concrete when the concrete is poured and can provide temperature readings, for example, that can be used to predict the strength development of a hardened concrete slab. Multiple commercially available sensors can be embedded in the concrete to indicate or generate a signal corresponding to the temperature and / or humidity state of the concrete. These include Giatec of Canada (SMARTROCK™ and BLUEROCK2™ sensors), Concrete Sensors Co. of Cambridge, Massachusetts (NOVOCRETE™ sensors), MATOlog of Finland (e.g., CURE™ sensors), Wake Inc. of Grandville, Michigan (HARDTRACK™ sensors), Quadrel LLC of Pittsburgh, Pennsylvania (vOrb™ sensors), Flir of Wilsonville, Oregon (INTELLIROCK™ sensors), and AOMS of Canada (LUMICON™ sensors).

[0047] Many of the above sensors measure humidity through electrical resistivity or capacitance measurements and include thermocouples and / or piezoelectric sensors for measuring temperature, which wirelessly transmit data signals to a portable device, a remote processor, and / or the cloud for real-time monitoring and logging of temperature, humidity, and other maturity data. The signal data of such sensors can be correlated with one or more physical properties (e.g., compressive strength at various times after batch processing), and can be used by the system processor of the slump monitoring system to adjust the current concrete load, such as by introducing one or more accelerators, retarders, or a mixture of both into the concrete.

[0048] Some of the sensors described in the foregoing section that can be embedded in concrete can also be used when positioned against or placed on the surface of the concrete. For example, one or more sensors can be affixed to the formwork or mold into which the concrete is poured, or can be coupled or fastened to reinforcing bars, facades, tunnel walls, foundations, or other structures into which the concrete is poured or sprayed.

[0049] Various exemplary embodiments of the present invention are described below, along with some further exemplary aspects of these various embodiments.

[0050] In a first exemplary embodiment, the present invention is a method for adjusting the delivery of concrete, comprising: (A) providing at least two delivery trucks, each having a mixer drum containing a concrete load and a processor control system for monitoring at least one hardening time value or range of values (e.g., initial hardening time, final hardening time, compressive strength or combinations thereof, or other values) of the rheology (e.g., slump, slump flow, and yield stress) and the concrete load within the drum, wherein the processor i. accessing, for delivery to a job site, at least one stored set time value or range of values assigned to the concrete loaded in the mixer drum; ii. calculating, based on hydration monitored over time, at least one current set time value or range of values for the concrete load; iii. comparing the at least one stored set time value or range of values with the at least one calculated current set time value or range of values; programming steps to perform functions including; (B) sequential placement of concrete loads poured from at least two delivery trucks adjusting the current set time value(s) or range(s) of values by introducing an accelerator, retarder, or mixture thereof into at least one of the at least two delivery truck concrete loads to perform or modify finishing, stripping, form removal, or compressive strength phases; A method is provided that includes.

[0051] In a first aspect of this first exemplary embodiment, a system for monitoring rheology (e.g., slump) can be based on the use of one or more hydraulic sensors (see, e.g., U.S. Patent No. 8,818,561 regarding sensors for both a charging pressure port and a discharging pressure port), a force sensor (e.g., a strain gauge or a stress gauge), an acoustic sensor, or a combination thereof. Various known rheology monitoring systems have been described above. A particularly preferred monitoring system is based on a hydraulic sensor in combination with a drum rotation speed monitor (e.g., a gyroscope, an accelerometer on the drum, or both). Any stored or current set time value or range of values can be generated, for example, by using an automatic slump monitoring system, preferably by monitoring the temperature change of a concrete load over time at a given concrete slump. Monitoring of the concrete load over time can be done in several ways. For example, the temperature of the concrete load is measured over time and can be considered along with the batch quantity (including the load size at the batch plant and any additional water or admixture added at any point in time, plus the age of the concrete). After being poured at the job site, the concrete loads can have several overlapping but preferably non-matching set time values or ranges of values. In another exemplary aspect, the first job site may not be the final "pour site", in which case the truck is routed differently to move from the first job site to another job site to deliver the full or partial load. Adjustment of the current set time value or range of values for the concrete load can be achieved, for example, by controlling the dosage of an accelerating agent, a retarding agent, or a mixture thereof.

[0052] In a second aspect of the first exemplary embodiment, the phrase appearing in section A(ii) above that includes "calculating at least one current curing time value or range of values of the concrete load based on the hydration monitored over time" can include one of many known methods for tracking the hydration of concrete over time, including, in addition to tracking temperature changes or rates of temperature change, known means for tracking water content, slump changes, or other aspects of the hydration state. Such tracking preferably includes information regarding the amount of cementitious material initially batched with the concrete components in the mixer drum, which can be obtained from a ticket issued by the batch plant.

[0053] In a third aspect of the first exemplary embodiment, at least two of at least two concrete delivery trucks carry concrete loads resulting from different batch plants.

[0054] In a second exemplary embodiment that can be based on the first exemplary embodiment above, the present invention provides a method in step (A) in which at least three delivery trucks (more preferably at least six trucks) are provided, each having a mixer drum containing a concrete load and a processor control system for monitoring the rheology and monitoring a curing time value or range of values of the concrete load within the drum, the processor being programmed to perform functions (i), (ii), and (iii) as described above, and each of the at least three delivery trucks (more preferably at least six trucks) adjusting a stored curing time value or range of values or a current curing time value or range of values of the concrete load.

[0055] In a third exemplary embodiment that can be based on the first or second exemplary embodiment above, the present invention provides a method in which both the stored curing time value or range of values and the current curing time value or range of values are adjusted.

[0056] In a fourth exemplary embodiment that can be based on any of the above first to third exemplary embodiments, the present invention provides a method in which a stored hardening time value or range of values is calculated based on factors including the estimated age of the concrete at the time of injection. The estimated age can be calculated, for example, based on traffic, job site conditions, or other factors.

[0057] In a fifth exemplary embodiment that can be based on any of the above first to fourth exemplary embodiments, the present invention provides a method in which the hardening time value or range of values is selected from time values for (a) the start of finishing, (b) the completion of finishing, (c) the step of removing the formwork or mold from the concrete, (d) the step of permitting pedestrian or vehicle traffic on the concrete, (e) the step of releasing a tensioned cable from a jack (used in prestressed concrete applications), (f) the step of anchoring or grouting a cable after tensioning (with respect to the concrete after tensioning), or (g) the step of pouring additional concrete on top of previously poured concrete.

[0058] In a sixth exemplary embodiment that can be based on any of the first through fifth exemplary embodiments described above, the present invention provides that a stored set time value or range of values accessed or accessed and adjusted by at least one of a delivery truck processor control system is (a) ticket information provided by a batch plant that procured the concrete in the truck mixer drum (e.g., the ticket information can include mix design, material batch weights, concrete load volume, water content or water / cement ratio, or combinations thereof), (b) a supervisor at a job site where concrete is poured from the truck mixer drum (e.g., the supervisor can take into account worker conditions including, but not limited to, ambient temperature, relative humidity, wind speed, UV index, traffic congestion, worker status, etc.), (c) a processor that receives data signals from humidity, moisture, and / or temperature sensors (or combinations of such sensors) embedded in, placed on the surface of, or embedded within the concrete poured or placed at or in another job site, or (d) derived from a processor that monitors a rheology and set time value or range of values of a concrete load of another concrete delivery truck having a processor control system for monitoring (e.g., a primary delivery truck or other delivery truck that injects concrete at a job site having previous set time values or ranges of values).

[0059] In a first aspect of the sixth exemplary embodiment, the humidity, moisture, and / or temperature sensors can be embedded within and / or placed on the surface of the poured concrete.

[0060] In a second aspect of the sixth exemplary embodiment, one or more sensors can be suspended above the concrete poured at the job site using an aerial drone, cable, pole, or other suspension means. Sensors preferred for this application can be selected from optical, infrared, acoustic, radio wave, microwave, electrical resistivity, capacitance, and ultrasonic sensors, or combinations thereof. These sensors can provide data signals indicative of the hydration state or rate of the concrete, and such data signals can preferably be transmitted wirelessly, such that a system processor mounted on the delivery truck can monitor the current hydration state of the concrete load, record and store the information, and as a result, use it as historical (memory) information and correlate it with a target set time value or range of values.

[0061] In a third aspect of the sixth exemplary embodiment, sensors (e.g., conductive, ultrasonic) can be used within a hose for injecting or depositing concrete at the job site, such as within one or more nozzles or hoses used for the spray application of shotcrete, for depositing concrete in a 3D printing process, or for extruding a concrete portion such as for making a tunnel or precast concrete shape.

[0062] In a seventh exemplary embodiment that can be based on any of the above-described first through sixth exemplary embodiments, the present invention provides a method further comprising the step of adjusting at least one stored curing time value or range of values, and the step of providing a report or indication of the adjustment made to the at least one stored curing time value or range of values. In a first aspect of this example, a delivery truck monitoring system uses at least one stored curing time value or range of values, such as an initial curing time, a final curing time, a time to remove the formwork from the concrete, and adjusts the stored value or range of values based on new data information obtained as described in the sixth exemplary embodiment above. Thus, a supervisor at a job site where concrete is being poured (or sprayed, or placed) can send an instruction to the processor to add 5 or 10 minutes to the curing time due to a delay at the job site. As another example, a remote processor, or even a processor used to monitor the concrete load on a delivery truck, can receive a data signal or other information derived from sensors embedded in, or placed on or against, previously poured concrete and adjust the stored curing time value, such that the truck system processor can adjust the current curing time value of the concrete load in the truck using the modified value. In a further example, the system enables recording or verification of the adjustment made to the stored curing time value or range of values.

[0063] In a second aspect of this exemplary embodiment, an adjustment to the stored curing time value is sent to, or retrieved by, a concrete monitoring system on another concrete delivery truck and can be used to adjust pouring and finishing events at the pouring site.

[0064] In an eighth exemplary embodiment that can be based on any of the above-described first through seventh exemplary embodiments, the present invention provides a method of comparing a current curing time value or a stored curing time value or range of values with at least one factor selected from the temperature of the concrete, the rate of change of the temperature of the concrete, the batch quantity or mix design of the concrete, the water or admixtures (e.g., cement dispersants, chemical or superplasticizing admixtures) added to the concrete load, the rheology (e.g., slump, slump flow, yield stress), or other properties of the concrete.

[0065] In a ninth exemplary embodiment that can be based on any of the above-described first through eighth exemplary embodiments, at least one of the concrete loads in at least one of the at least two delivery trucks is return concrete (e.g., returned from the same or a different job site and possibly containing a set retarder admixture administered to a partial residual load in the mixer drum), and further, the comparison of the stored curing time value or range of values with the current curing time value or range of values includes taking into account the age of the concrete from the first batching of the concrete returned from the job site.

[0066] In a tenth exemplary embodiment that can be based on any of the above-described first through ninth exemplary embodiments the first concrete load from the first delivery truck is injected at a predetermined location, and while the first concrete load is in a plastic state, the second concrete load from the second delivery truck is injected over the first concrete load, and the first load and the second load have overlapping curing time values or ranges of values.

[0067] For example, in U.S. Patent No. 7,968,178, Scurto et al. disclose that a first slab of concrete can be poured onto a first concrete slab while still in a somewhat plastic state in order to create an integrated area between the continuously poured slabs. In this way, the present invention facilitates the bonding between concretes poured, sprayed, printed, deposited, or placed on a previous concrete that is still in a plastic state, such as during continuous or adjacent concrete delivery at a job site, by allowing the hardening time values or ranges of hardening times to slightly overlap. In the construction industry, one may hear a contractor talk about pouring a "first lift" (e.g., the mass or composition of the first concrete) and then pouring a "second lift" on top of the first lift. This is often associated with self-consolidating or self-compacting concrete. Concrete can be poured quickly due to its fluidity, but flowing concrete can exert a large force on the formwork, increasing the risk of "bursting" where the formwork fails catastrophically. Based on the adjusted hardening time, the flowing concrete can be left to harden so that the next "lift" can be safely poured.

[0068] In an eleventh exemplary embodiment that can be based on any of the first through tenth exemplary embodiments described above, the present invention provides a method in which a stored hardening time value or range of values of concrete pre-delivered and placed at a job site is obtained or derived from data signals generated by at least one sensor within a nozzle, hose, or other conduit of the concrete during deposition or spraying of the concrete through the nozzle, hose, or conduit at the job site. For example, the sensor can be an electrical conductivity sensor (or two electrodes spaced apart within the nozzle and / or hose that can send an electric current through the electrodes and measure the conductivity of the concrete), or the sensor can be a sensor of the aforementioned type (e.g., infrared (IR), ultrasonic).

[0069] In a twelfth exemplary embodiment that can be based on any of the above-described first to eleventh exemplary embodiments, the present invention provides a method in which a part of at least one concrete load of a delivery truck is injected at a first work site, and within 15 minutes, more preferably within 10 minutes, from the injection, a single dose of a setting retarder is introduced into the remaining part of the concrete load in the delivery truck, and the remaining part is transported by the delivery truck to a second work site and injected at a predetermined position at the second work site. In a further aspect of this example, at least one subsequent dose of the setting retarder is administered to the remaining part of the concrete load during the movement from the first work site to the second work site.

[0070] In a thirteenth exemplary embodiment that can be based on any of the above-described first to twelfth exemplary embodiments, the present invention provides a method in which at least five (more preferably at least ten) delivery trucks are provided according to step (A) having a concrete load, wherein a setting time value or range of values is adjusted according to step (B), and the adjustment is carried out using a calculation of the setting time value or range of values based on signal data obtained or derived from at least one sensor arranged at the work site for monitoring the hydration of the concrete over time.

[0071] In a first aspect of this thirteenth exemplary embodiment, the hydration signal data over time of a plurality of concrete placement locations at the work site is optical, infrared, acoustic, radio wave, microwave, electrical resistance Generated by at least one sensor selected from a resistivity, capacitance, and ultrasonic sensor, and the at least one sensor is preferably moved over the concrete placement location using an aerial drone. A processor, such as a processor used to monitor the rheology of a truck concrete load, can be programmed to compare the obtained data signal with a previously stored data signal to obtain a hardening time value or range of values that correlates with the hydration data over time obtained from the at least one sensor. Further, in an exemplary embodiment, a processor such as a personal computer, laptop computer, or portable smartphone or smartwatch can be used to generate a drawing or map of a plurality of concrete placement locations along with a hardening time value or range of values, or a proposed sequence priority based on the hardening time value or range of values, thereby providing an indication of an arrangement suitable for sequential processing with respect to (a) the start of finishing, (b) the completion of finishing, (c) the step of removing the formwork or mold from the concrete, (d) the step of permitting pedestrian or vehicle passage on the concrete, (e) the step of releasing the tensioned cable from the jack (e.g., as used in prestressed concrete applications), (f) the anchoring or grouting of the cable after tensioning (e.g., for concrete after tensioning), or (g) the step of pouring additional concrete on top of the previously poured concrete.

[0072] In a second aspect, the hydration state of variously arranged concrete sections can be displayed on a visual monitor with respect to the darkened sections corresponding to the hydration state in the dark, or from the perspective of other visual aids.

[0073] In a fourteenth exemplary embodiment that can be based on any of the first through thirteenth exemplary embodiments described above, the present invention also provides a method for monitoring the hardening time conditions of a placed concrete load, the method comprising To obtain a data signal indicating hydration, moving at least one aerial drone having at least one sensor (e.g., a sensor selected from optical, infrared, acoustic, radio wave, microwave, electrical resistivity, capacitance, and ultrasonic sensors) over a plurality of concrete placement locations at a work site to monitor the hydration of the placed concrete over time; Comparing the obtained data signal with previously stored data signals to obtain a hardening time value or range of values correlated with the hydration data over time obtained from the at least one sensor; Generating a drawing or map of the plurality of concrete placement locations with the hardening time value or range of values, or a proposed sequence priority based on the hardening time value or range of values, thereby providing an indication of an arrangement suitable for sequential processing with respect to (a) starting finishing, (b) completing finishing, (c) removing the formwork or mold from the concrete, (d) permitting pedestrian or vehicle passage on the concrete, (e) releasing a tensioned cable from a jack (e.g., for prestressed concrete applications, etc.), (f) anchoring or grouting the cable after tensioning (e.g., for concrete after tensioning, etc.), or (g) pouring additional concrete on top of the previously poured concrete; Including.

[0074] In a first aspect of this 14th exemplary embodiment, the drawing or map can be generated on a portable device or, alternatively, on goggles worn by a field supervisor. The drawing can be, for example, a photograph or image of a concrete delivery truck as seen on an injection site map, enabling digital values and / or colors to be overlaid on the truck image or concrete segment image. Thus, the field supervisor can, according to the visual information regarding the injection state (i.e., the hardening time value), line up for injection or It can be instructed to the delivery truck to do so, and / or the finishing workers can be directed to those segments of the injected concrete having the required set values or characteristics.

[0075] Figure 3 is a block diagram showing an exemplary process according to a particular embodiment of the present invention. First, concrete is delivered to the placement location (block 22), and then the concrete is injected, spread, and hardened (block 24). For each concrete delivery truck load (or group of concrete delivery truck loads) of the concrete thus placed, a UAV (or fleet of UAVs) can use remote sensing based on optical and thermal signals to determine one or more outer perimeters of the placed concrete (block 26). For example, since the formwork and the concrete usually have different temperatures, the color difference (determined from the comparison of successive images), or the thermal signature from the concrete, can depict the injected concrete from the formwork edge or pre-placed concrete. Alternatively, image analysis comparing before and after injection can also help to determine the outer perimeter of the placed concrete. Using this information, for example, a database accessible to the processor can be uploaded together with the identification of the concrete delivery truck that delivered the concrete (e.g., the concrete delivery truck number), the batch ticket (containing the concrete components or mix design, e.g., the water content), the time when the concrete was injected, and the location of the concrete. This information helps to determine whether all sections of the form are properly filled, and if not, the contractor can be warned to vibrate and add more concrete.

[0076] Also, as shown in FIG. 3, the concrete article can be monitored for different properties (blocks 30, 32, 35, 36, and 38). For example, the UAV can scan the injected concrete article for differences in density that may indicate compaction problems to be addressed before the concrete hardens. Available techniques that can be used by the UAV to perform this include nuclear densitometers, ground penetrating radar, or capacitance energy dissipation (see, e.g., U.S. Pat. No. 5,952,561). The inventors also envision that air-coupled surface wave measurements can be used in the present invention (see, e.g., U.S. Patent Application Publication No. 2013 / 0289896). If a density difference is found (block 40), the affected area can be relayed to the contractor, for example, by a mobile application, whereby the contractor can visually see where compaction needs to be addressed by further compression or vibration. This can be accomplished, for example, by inserting a vibrating rod at the designated location, and additional concrete may even be required. Additionally, an augmented reality method can be utilized to more easily view the area of concern (see, e.g., U.S. Pat. Nos. 8,922,590 and 8,943,569, both of which are hereby incorporated by reference).

[0077] After placement and compaction, the UAV (drone) can periodically scan the topography of the concrete article using an imaging device such as photogrammetry or terrestrial laser scanning, for example, to determine areas of high and low spots that may require rework. During the screeding process and the initial floating process (which includes pressing and leveling, straight edging, and finishing troweling), the UAV can periodically scan the concrete article to determine properties such as surface moisture, which can be determined by, among other methods, photogrammetry (e.g., light reflectivity, or comparison of past and current images), water-sensitive near-infrared detection (see, e.g., U.S. Patent No. 7,265,846, incorporated herein by reference), radar (see, e.g., U.S. Patent No. 9,207,323, incorporated herein by reference). The periodic scans can include continuous scans, or can include fly-bys, for example, every 5 minutes, or every 10 minutes, but based on the rate of hardening of the concrete or changes in the rate of hardening It is thought necessary to perform frequently. The fly-by routes can also be changed, for example, based on the area of the concrete article being monitored, or simply on unobstructed flight routes. Once measurements are collected over time and spatially across the concrete article, a predictive mathematical model can be constructed to be able to predict surface moisture. Such a model can be used to send useful information to the contractor at the construction site. A mobile application or augmented reality method can be used on a laptop or smartphone device to, for example, indicate sections of the poured concrete having surface moisture that will soon exceed a predetermined threshold, whereby the contractor can determine where and when screeding and initial floating must be completed (see block 42 in Figure 3). Screeding and / or initial floating outside the applicable workability window can lead to dusting or scaling of the concrete surface and thus to repair costs that should be avoided.

[0078] Figure 4 shows an aerial view of the injected concrete slab. This begins the consideration of how a useful mathematical model can be generated to produce a visual representation of the hardening time behavior of the injected slab. Moisture measurements are taken in two injection compartments A and B (shown side by side for convenience). Figure 5 shows the moisture content of each slab compartment A and B (66 and 75%) at a specific time (t = 20 minutes). The measurement locations do not need to be aligned in a grid pattern or taken consistently at the same location. For the purposes of this consideration, the positions of the measurements over time are kept constant. The measurements are taken over time at each of two positions (A and B shown in Figure 4). As more data is collected, the model can be refined in real time. In other words, for each new data point collected, the model is reconstructed or refined to take into account the new data. The prediction model aims to detect one or more features of the data curve related to the monitored property over time (e.g., temperature, strength, hardening time, or moisture). The features can be local or global extrema (e.g., peaks or valleys), or inflection points, or simply exceeding or falling below a predetermined threshold. In this case, it is assumed that the inflection point of the curve representing moisture over time represents the optimal time to finish the concrete. Here too, to finish the concrete, the minimum stiffness of the slab and the maximum moisture on the surface are required. Furthermore, as the concrete hardens and more water leaves the surface, finishing becomes more difficult. Therefore, there is an optimal time.

[0079] In FIG. 5, the generation of complete moisture after the optimal time is plotted for each compartment. The markers "O" and "X" represent the collected data, while the lines represent a logistic function fit using the standard least squares method. The shaded areas indicate the finishing windows suitable for compartments A and B. This can be determined by comparison between historical data, for example, by directly measuring the finishing window and comparing it with the penetration test (see, for example, ASTM C403-16) of the sensor data signal obtained over the same period. As can be seen from the figure, the inflection point is within the window. Therefore, if the inflection point can be determined in real time, the contractor can be warned to start the finishing process.

[0080] In some cases, it may be more useful to warn the contractor at the start of the finishing time window rather than at the center of the window. In this case, the second derivative can be calculated using standard computational techniques for the assumed form of the function that fits the data (such as a logistic function, quadratic function, linear function, etc.). The second derivative with respect to time can be numerically calculated using finite differences. Although the latter process may require smoothing of the original data, it is not necessary to assume an assumed function form (such as a logistic function), which can be an advantage when it is difficult to determine the form of the function in advance.

[0081] FIG. 6 is a graph diagram of another exemplary embodiment, and a second derivative can be used to generate higher resolution data in order to propose when finishing can be started or completed.

[0082] Furthermore, additional analysis can be performed to predict the time values at which finishing can start and end. Taking the third derivative with respect to time can help monitor how close the third derivative, which indicates the maximum or minimum of the second derivative, is to zero. Based on how quickly the third derivative converges to zero, the times at which the maximum and minimum values occur (and thus the start and end of the finishing window) can be predicted and reported to the contractor or other job site personnel.

[0083] After initial floating operations are performed, slight stiffening of the concrete must be done before edging or joining is carried out, and such stiffening is described as "maintaining (a) foot pressure with a slight depression of about 1 / 4 inch (6 mm)". See, for example, ACI 302.1R-15. Alternatively, drone-mounted sensors can be used for periodic monitoring of properties such as the rigidity of concrete via pressure means (e.g., a force probe or penetrometer attached to the drone), via an ultrasonic transducer / receiver / transmitter unit for measuring shear or Rayleigh waves, or, as another example, via an electrical resistivity or temperature sensor. By continuously measuring over time and space (the area of a concrete article such as a slab), a predictive mathematical model can be constructed to predict stiffening as described above. For example, monitoring temperature for initial curing can indicate the time to finish the concrete article. By taking the second derivative of temperature with respect to time (using an assumed function or via finite differences), the maximum of the second derivative can indicate initial curing. As described above, a similar approach can be taken using the output from other sensors. This information can be presented using such a mathematical model to provide a visual indication of which portions of the injected concrete section are sufficient (e.g., exceed a predetermined threshold). Using this information, the contractor can instruct the finisher to start power floating and troweling on a particular section of the concrete. The placement order of the concrete may, for example, not be able to accommodate sections that need earlier attention because concrete placed in areas more exposed to the sun or wind to a greater extent may accelerate the curing time behavior, or, for example (see, e.g., block 44 of FIG. 3), discrepancies in the truck loading of the concrete can also change the curing time behavior.

[0084] Once the power floating is completed, during the troweling operation, the UAV can periodically scan the concrete article and determine the surface color and texture by optical remote sensing or terrestrial laser scanning (block 46 in Figure 3). Continuous measurements over time and space (in the area of the article, e.g., the area of a slab) relay out-of-specification (e.g., by color analysis) or unfinished positions (e.g., by texture analysis) to the contractor (again, e.g., via a mobile application or augmented reality method), enabling comparison between positions so as to indicate areas where troweling is no longer necessary and areas that still require finishing (block 50). This can prevent harmful surface color and texture variations.

[0085] Figures 4 to 6 show the use of a simple grid time and space model consisting of two sections where the measurement values are collected at the center of the section at regular intervals, while Figures 7a to 7d show a more complex but more generalized method by which a prediction model can be developed through the use of data collected using one or more sensors mounted on an unmanned aerial vehicle (UAV), commonly referred to as a drone.

[0086] In Figure 7a, 50 virtual measurement values have been collected by using the sensors on the drone , Each measurement location is indicated by a circle with a number next to it. The measurements do not need to be taken in a regular grid pattern. In each of 7a - 7d, a Voronoi diagram was created using 50 measurement values. Each Voronoi "cell" is the area associated with each measurement. This is a standard way of dividing an area into regions based on groups of points within the area. Essentially, for each measurement, the region or cell is defined as all the areas that are closer to that measurement than to any other measurement. Figure 7a uses shades of gray for each region corresponding to the normalized values. For example, this can represent moisture, temperature, or stiffness of an article, or even acoustic measurements. Figure 7a further shows the normalized values across the article 10 minutes after a reference time (e.g., when the concrete was placed, or when the concrete was batch - processed).

[0087] Figures 7b - 7d show subsequent virtual set - time value (hydration state) measurements using one or more sensors on a drone (UAV) placed over various sections of the injected concrete at 30 minutes, 60 minutes, and 80 minutes respectively after the reference time. The measurement locations do not necessarily have to be in the same positions as in the previous period. If different positions are measured over time, preferably, a large number of measurements should be taken to obtain a representative sampling. It is assumed that areas that behave similarly in the injected concrete can be grouped together (e.g., if the temperature difference between two is below a predetermined threshold). As time passes, as shown in the exemplary embodiments shown in Figures 7a - 7d, the shaded regions become darker, but not all at the same rate. In particular, the lower - right corner does not become dark as fast as the rest of the article. This could simply be the result of this section being injected at a later time than the rest of the article, or could be due to more complex reasons such as the concrete mixture not being the same (e.g., different water content in a particular load). In any case, for each region (in this case, the lower - right corner region and the complementary region), the data collected for each period can be used to develop relationships or models over time.

[0088] Figure 8 shows a hypothetical example of the model proposed above. Each marker represents an average sensor measurement or data signal value for a particular area over a given period. At 60 minutes, the data is used to fit the model to predict the future behavior represented by the dotted portions of each curve. The horizontal dashed line can represent a threshold that triggers a finishing event such as "starting power floating". This trigger point can be determined by comparing the measurement with empirical data obtained from past deliveries. More preferably, a specific characteristic (or combination of characteristics) can be correlated with the trigger point.

[0089] Figure 8 also shows how a logistic function can be used in the model. The trigger point can be correlated with the inflection point of the logistic data curve, for example, the point where the curve changes from concave to convex (or vice versa). Using this example, the power floating of the concrete portion shown in the lower right area of Figure 7c can start in about 20 minutes, and the power floating of other compartments can start in about 3 minutes. This prediction tool can prevent serious surface damage from power floating activities that are too early or too late (for example).

[0090] Many different sensors can provide measurements both in time and space to obtain information indicating when different stages of the finishing process start and end. Relationships can be developed between physical phenomena such as changes in surface moisture or stiffness of concrete articles. Some of these relationships, for example, the relationship between the penetration test and slab stiffness, exist in the literature. Other relationships require more detailed analysis and additional parameters. For example, when using optical sensors, machine vision (see, for example, Machine Vision, R. Jain, R. Kasturi, B. Schunck) is a useful mathematical tool for extracting characteristics on subsequent images that may be related to changes in surface moisture. It can become a rule. The determination of color, shading, and texture characteristics can be particularly useful. For example, subsequent images over time (see, for example, Machine Vision, R. Jain, R. Kasturi, B. Schunck, pp. 234-248) can be analyzed using average intensity, entropy, energy, contrast, uniformity, and correlation calculations. Different characteristics are more or less sensitive to different situations (e.g., indoor slab vs. outdoor slab).

[0091] In addition to improving finishing work, drones have other applications. For example, using the same method of collecting data from concrete articles in both temporal and spatial ways, mathematical models of temperature, hydration (e.g., initial and final setting), concrete strength (e.g., via maturity methods such as ASTM C1074-17), and moisture changes over time can be generated. When each point or group of points is recorded, the sensor measurements can be supplied to a processor to regenerate a prediction model or update it to include new data points. Thus, the prediction model adapts to new data and is not just a static model. This prediction can further enable a contractor to make logistic decisions at the job site.

[0092] Furthermore, the hardening time prediction (initial hardening and final hardening, as well as the time to start or the time when the surface finish can be completed) can be recorded along with all other data related to the concrete, including which concrete delivery truck load contributed to the concrete article section, the batch weight of each concrete delivery truck load, the slump of each concrete delivery truck load, other rheological properties of the concrete delivery truck load, the air content of the concrete delivery truck load, the total water amount and admixture dosage administered during transportation of each concrete delivery truck load, etc. As these data are generated, they can be collected and recorded in a database to generate an additional prediction model that associates the relevant data for a given load (i.e., pre-injection data) with post-injection data including the hardening time. Thus, for a given concrete delivery truck load destined for a specific job site, the hardening time can be predicted. This is shown through Example 4 described later.

[0093] Alternatively, the estimated hardening time can be obtained by assuming that a particular load of the same job has a hardening time similar to that of a previous load when the pre-injection conditions are similar (e.g., the total water content is within 5 pounds per cubic yard of concrete, or the slump is within 1 inch, etc.). By using the predicted hardening time and comparing it with the target hardening time, the difference in hardening time can be established. Based on this difference, along with any additional time required, the appropriate dosage of a hardening retarder can be calculated and managed to adjust the concrete hardening time, and as a result, the placement of the concrete route or route change can be adjusted as explained in the detailed description of the following hypothetical illustrative example.

[0094] Figure 9 shows an example of two batch plants, each of which typically supplies two job sites. The present invention enables sending a partial or complete load that is unused or rejected at one site directly or indirectly to the other site. Plant 1 (P of 102 1 ) and job site A (J of 104A ) and the route 110 therebetween has a transport time of 45 minutes (one way). The transport time of the route 114 from Plant 1 to the work site B (J of 108 B ) to is 25 minutes. The transport time of the route from Plant 2 (P at 116 2 ) to J B is a transport time of 10 minutes. The transport time of the route 116 between P 2 (106) and J A (104) is 6 minutes. The transport time of the route 118 between the two work sites J A and J B is 12 minutes.

[0095] Referring to FIG. 9, for purposes of illustration, assume that Plant 1 (102) is dedicated to delivering to work site A and Plant 2 (106) is dedicated to delivering to work site B (108). In this case, the present invention enables a scenario where the concrete from plant 1 is rejected at work site A (104), but can be delivered to work site B (108). To receive a ticket authorizing this route change or to perform adjustments for mixing (e.g., adding cement), the concrete delivery truck typically has to travel route 110 in both directions (i.e., it has to return to plant 1 at 102), and then travel route 112 to work site B at 108. The total time required for this travel distance is 45×2 + 25 = 115 minutes (excluding the time required to receive the ticket and adjust the concrete). Normally, work site B (108) receives concrete from plant B (106) via route 114, which usually only takes 10 minutes. Therefore, the rejected delivery from plant 1 is 105 minutes older compared to a typical delivery from plant 2 to work site B moving along route 114 (115 minus 10 = 105). Thus, it is not surprising that the finishing time of the concrete from plant 1 is different compared to the concrete from plant 2. This leads to a serious problem because the concrete from plant A may harden 105 minutes earlier compared to the concrete normally delivered from plant B (106) to work site B (108).

[0096] Referring to FIG. 9, assuming for the purpose of illustrating another example, if it is considered that the concrete from plant 2 (106) to job site B (108) by route 114 is rejected for use at job site B and then for the purpose of reuse at job site A, the delivery truck usually has to travel route 114 twice (usually has to return to plant 2 to obtain a ticket authorizing delivery to job site A), and then has to travel the movement route 116 to job site A. The total time (again, not including the time to receive a new ticket and adjust the mix design) is 10×2 + 6 = 26 minutes. This is 19 minutes shorter than the typical concrete delivery from plant 1 to job site A. The concrete from plant 2 arrives at job A earlier and hardens 19 minutes later compared to the concrete from plant 1.

[0097] In a further exemplary diagram based on FIG. 9, assume that plant 1 (102) is dedicated to delivery to job site A (104), while plant 2 (106) is dedicated to delivery to job site B (108). Also assume that the concrete load delivered from plant 1 to job site A is rejected, but can be delivered to job site B. In an exemplary embodiment of the present invention, an electronic ticket can be issued as soon as it is confirmed that the concrete delivery truck is delivering to job site B. This eliminates the need to return the concrete delivery truck located at job site A to plant 1. The delivery time from plant 2 to job site B can be sent to the processor for the concrete management system that controls the monitoring of the concrete load on the concrete delivery truck. This can be based on, for example, the time of the last delivery, the average of several past deliveries, or an early prediction of the next delivery. The processor also receives an estimate of the current concrete delivery truck's time to reach job site B from job site A, including the time the concrete has already been moving from plant 1 to job site A. In this case, the delivery time from plant 2 to job site B via route 114 is 10 minutes, and the total delivery time from plant 1 to job site A and from job site A to job site B is 57 minutes. Thus, the concrete from plant 1 is 47 minutes older than the concrete from plant 2. In this case, the processor calculates the amount of retarder needed to delay the concrete by 47 minutes, and the retarder is administered to the concrete delivery truck accordingly. The administration can be performed manually or automatically.

[0098] FIG. 9 also allows for considering a further scenario enabled by the present invention where the concrete delivery from plant 2 (106) to job site B (108) is rejected for use at job site B but can be used at job site A. In this case, the plant When a delivery from Plant 2 to the work site B occurs and concrete is needed for the work site A, an electronic ticket can be issued (for example, to a processor control management system installed on the delivery truck), thereby eliminating the need for the truck to return to Plant 2 and then eliminating the need for it to move from Plant 2 to the work site A. The delivery time from Plant 1 to the work site A can be sent to or stored in the truck, and an estimated value for the current concrete delivery truck to reach the work site A including the time already traveled can also be considered. Thus, in this example, the delivery time from Plant 1 to the work site A is 45 minutes, and the total delivery time from Plant 2 to the work site B and from the work site B to the work site A is 22 minutes. Therefore, the concrete from Plant 2 is batched 22 minutes after the batch time of the concrete normally delivered from Plant 1 to Plant 2. In this case, the processor calculates the amount of accelerator needed to accelerate the concrete by 22 minutes, and the accelerator is put into the concrete delivery truck. The accelerator can be administered either manually or automatically. Alternatively, the driver of the concrete delivery truck or the work site adjuster is instructed to wait approximately 22 minutes before injecting the concrete.

[0099] In a further example of the advantages and features of the present invention, referring to FIG. 9 as an illustration, assume that plant 1 (102) is dedicated to delivery to job site A (104), and plant 2 (106) is dedicated to delivery to job site B (108). Also assume that a concrete delivery truck moving from plant 1 to job site A is rejected, but can deliver to job site B. In addition, the current mix design of the concrete delivery truck needs to be adjusted to match the mixing requirements of the concrete goods at job site B. As soon as it is confirmed that the concrete delivery truck will deliver to job site B, an electronic ticket is issued. The processor accessible by the concrete delivery truck receives the delivery time from plant 2 to job site B. This can be based on, for example, the time of the last delivery, the average of several past deliveries, or a forward prediction of the next delivery. The processor also receives an estimated time value including the time already traveled for the current concrete delivery truck to reach job site B, and an estimated time value required to adjust the mix design in the concrete delivery truck including batch processing at a given plant. At this point, the processor is programmed to consider two alternatives. The first alternative is for the concrete delivery truck to return to plant 1, adjust the mixing, and move to job site B. The second alternative is for the concrete delivery truck to move to plant 2, adjust the mixing, and move to job site B.

[0100] In the first alternative, the total time between plant 1, job site A, back to plant 1, and job site B (via routes 110, 110, and 112) is 45×2 + 25 = 115 minutes (excluding the time to adjust the mix design). The time difference between this travel time and the estimated time between plant 2 and job site B is 115 - 10 = 105 minutes. Therefore, a retarder is required. In this alternative, at job site A, the retarder is (automatically or manually) administered to the concrete to adjust it for 105 minutes. When the concrete delivery truck is adjusted at plant 1, additional material can be added to introduce the retarder to cover the travel time between plant 1 and job site B. The total dosage can be added at job site A.

[0101] In the second alternative, ignoring the time to adjust the mix design, the total time between plant 1, job site A, plant 2, and job site B (numbers 110, 116, and 114) is 45 + 6 + 10 = 61 minutes. The time difference between this travel time and the estimated time between plant 2 and job site B is 61 - 10 = 51 minutes. Again, a retarder is required. However, in this case, if the retarder is introduced taking into account the time between plant 1 and between job site A and plant 2 (including any time required to adjust the mix design), the remaining portion of the move is the same as a direct delivery between plant 2 and job site B, so no further adjustment is required.

[0102] In the above example, for the sake of simplicity in calculating the time difference, the time for adjusting the mix design was not included. If the mix design is to be adjusted, those skilled in the art based on the disclosure herein will understand how to adjust the time to compensate for the exact age of the concrete. In both of these cases, a "dribble dose" can be used. Thus, instead of measuring the exact dosage of the retarder, for a certain period, for example 15 minutes, a sufficient amount of retarder to obtain the effect is added. After this period has elapsed, if more retarder is required, another dosage is added, and so on. This is discussed and illustrated in Example 5.

[0103] The embodiments disclosed herein are described herein using a limited number of exemplary embodiments, but these specific embodiments are not separately described and are not intended to limit the scope of the invention claimed. There are modifications and variations from the described embodiments. More specifically, the following examples are given as specific illustrations of the embodiments claimed. It should be understood that the embodiments are not limited to the specific details described in the examples. All parts and percentages in the examples and the rest of this specification are by percentage of dry weight unless otherwise specified.

[0104] Example 1 Figure 10 graphically shows the experimental optical measurements over time of a concrete slab. 564 pounds per cubic yard (lbs / yd 3 ) of cement, 1700 lbs / yd 3 of stone, 1425 lbs / yd 3 of sand, 300 lbs / yd 3A concrete mixture containing water and 7.5 ounces per 100 pounds of a cementitious material (oz / cwt) of WRDA® 64, a low-range water reducer (LRWR). The concrete was mixed according to the following protocol. 80% of the stone, sand, and water were mixed at high speed for 2 minutes. The remaining water was added to the cement and mixed at high speed for 2 minutes. The LRWR was added and mixed at high speed for 2 minutes. The mixer was turned off and the concrete was left to stand for 3 minutes. Mixing was resumed at high speed for 3 minutes. After mixing, a portion of the concrete was tested for slump and air, and the remaining concrete was poured into 2-foot by 3-foot by 6-inch slabs, screeded, and hand-troweled. Thereafter, images were acquired every 5 minutes from a fixed camera (which is assumed to be replaced by a UAV according to the embodiments disclosed herein). From each image, the average, median, and standard deviation of the grayscale were determined using typical image analysis tools (see, e.g., Solomon, C. and Breckon, T., Fundamentals of Digital Image Processing: A Practical Approach with Examples in Matlab, Wiley-Blackwell).

[0105] From top to bottom, plot the following values, the ratio of the median to the mean, and the ratio between the median and the standard deviation over 90 minutes in FIG. 10. This data is useful for formulating a mathematical model. In this case, a generalized logistic function was fitted using standard regression tools. Using these equations, the time at which the gloss of water disappears from the concrete surface of a given concrete section can be predicted, and thus the contractor can know when to move on to the next section for finishing. As described above, measurements such as in this example can be made using a UAV-based sensor, and in combination with the ability to automatically collect measurements across the slab over time, can enable the contractor to better understand the hardening time behavior of the concrete to ensure proper finishing..

[0106] Example 2 The second concrete was prepared and mixed in the same manner as in Example 1. The mix design was 625 pounds per cubic yard (lbs / yd 3 ) of cement, 1700 lbs / yd 3 of stone, 1450 lbs / yd 3 of sand, 300 lbs / yd 3 of water and 4.5 ounces per 100 pounds of ADVA (registered trademark 190 of cementitious material (oz / cwt), changed to a high-range water reducer (HRWR). A 2 feet × 2 feet × 6 inches slab was produced in the same manner as in Example 1 and monitored over time by a fixed camera (here again, assumed to be replaced by a UAV-based sensor). Different from Example 1, the position of the slab was placed in an area where the lighting was variable (e.g., changes in clouds / sunlight). In FIG. 10, the central intensity of each image is shown over time. In this example, there is an insufficient display of the trend over time. However, using a texture analysis algorithm (e.g., see Machine Vision, R. Jain, R. Kasturi, B. Schunck, pp. 236-238, incorporated herein by reference), the correlation between the sensor data and the hardening time value of the concrete can be improved.

[0107] As shown graphically in FIG. 11, the contrast analysis results are much clearer than those shown using only the central intensity. Furthermore, the minimum value, which is a characteristic of the curve, can be correlated with the time to start the power floating process.

[0108] Example 3 The same concrete sample observed by the fixed camera in Example 2 above was observed using a near-infrared sensor sensitive to wavelengths in the range of 750 - 1000 nm. As shown in FIG. 12, after about 150 minutes, the sensor readings began to decrease linearly. This corresponds to the minimum value of the contrast of the gray-level co-occurrence matrix in Example 2. As a result, this change in behavior can be used to provide an indication or signal regarding when power floating can start.

[0109] Example 4 Pre-injection data The system can be programmed to collect data from each concrete delivery. First, record the batch weights including the amounts of cement, aggregates, water, and admixtures and store them in a database. The batch time is also added to the database. The temperatures of the materials can also be added to the database. During delivery, any water or admixtures added to the concrete delivery truck are added to the database. At the time of discharge, record the final concrete temperature, current ambient temperature, slump (or slump flow), air content (e.g., from a sensor such as those commercially available under the CiDRA® brand), drum revolutions, time from batch, and concrete volume. All data up to this point can be considered pre-injection data. To simulate this, 29 concrete mixtures were tested in the laboratory. The same basic mix design was used with ASTM Type I cement at 565 pounds per cubic yard (pcy), coarse aggregates at 1700 pcy, fine aggregates at 1425 pcy, and water varying between 260 and 300 pcy. A high-range water reducer (HRWR) (e.g., ADVA® 198 water reducer from GCP Applied Technologies) was used at 4.00 ounces (oz) per 100 pounds (cwt) of cement, and an air-entraining agent (e.g., DAREX® II AEA also available from GCP) was used at 0.4 oz / cwt. All mixtures were mixed using the following protocol. 1) Place all of the coarse and fine aggregates in the mixer with 20% of the water and the air-entraining agent. 2) Mix at high speed for 1 minute. 3) Add the cement and mix at high speed for 2 minutes again. 3) Add the HRWR while continuing to mix for an additional 2 minutes. 4) Stop the mixer and let it stand for 3 minutes. 5) Resume mixing at high speed for 2 minutes. 6) Reduce the speed and mix for an additional 1 minute. Finally, 7) stop the mixer and start the test. Of the 48 mixtures, 9 mixtures did not have AEA, the curing temperature was 2°C for 8 mixtures, and the curing temperature was 38°C for 8 mixtures. For the remaining 23 mixtures, the curing temperature was 20°C. Each mixture was tested for pre-injection data, slump, and air content.

[0110] The post-injection data system also records the post-injection data. To simulate this, for each mixture tested for pre-injection characteristics, post-injection characteristics including initial setting time, final setting time, and strength at 1, 3, 7, and 28 days were also tested. The initial setting time and final setting time were estimated by analyzing the temperature change of 4×8-inch cylinders using typical methods (e.g., www.intrans.iastate.edu / research / documents / research... / CalorimeterReportPhaseIII.pdf). All data were recorded in a database.

[0111] Based on the pre- and post-injection data, a random forest model was developed to predict the final setting time. The data were split into a training set (29 mixtures) and a test set (19 mixtures). Both sets included samples with different AEA contents, water contents, and curing temperatures. Using random forest model (see, e.g., https: / / en.wikipedia.org / wiki / Random_forest) analysis, the model shown in Figure 13 was developed, where the x-axis is the actual setting time and the y-axis is the predicted setting time. The isoclines are plotted together with the predicted points of the test set. The model was developed using the pre-injection characteristics of slump, air, water content, and curing temperature. This curing temperature can be determined using current and near-future weather conditions at the injection site. Thus, data from weather applications can be used to calculate the curing temperature.

[0112] Note that the model can be developed using various methods. When there is a sufficient amount of data generated, machine learning techniques including supervised learning (e.g., support vector machine, Bayesian method, random forest method, etc.) and unsupervised learning (k-means clustering, neural network, etc.) become applicable. This is particularly suitable when considering two or more mix designs. Thus, the input to the model can be the batch weights of each component in addition to those used in this example.

[0113] In the developed model, the hardening time can be predicted based on the information before injection from the concrete load, and these predictions can include slump, air, water content, and hardening temperature values or ranges of values.

[0114] The predicted hardening time value can be compared with the hardening time of the already placed concrete. To adjust the hardening time of the concrete load, the difference between the predicted hardening time and the placed hardening time (based on any other optional time required before injecting the concrete) can be set, for example, as an input to a model that calculates the appropriate dosage of the hardening retarder. These models take the hardening time adjustment as an input (e.g., an additional 30 minutes) and output the retarder dosage (e.g., 3 ounces / cwt). Concrete manufacturers typically use hardening retarders to adjust the hardening time of the mix design (however, usually the retarder is added only at the batch plant), but there is this general understanding of dosage and hardening time adjustment, and the inventors believe it can be easily adapted to the in-transit / delivery injection method of the present invention. Thus, the standard model can be used for all mixes, but as more data is collected (e.g., the dosage administered and the measured hardening time adjustment obtained as a result), it is envisioned that the model resulting from the implementation of the teachings of the present invention can be refined by increasing the amount of data collected. Additionally, additional inputs to the model such as mix design, batch weight, and pre-injection data (e.g., slump, air) can be used. Again, this problem can be helped by machine learning techniques.

[0115] After the hardening retarder dosage is calculated, the hardening retarder can be administered into the concrete drum to adjust the hardening time.

[0116] Example 6 The data from Example 5 was re-analyzed using the "difference" method instead of the absolute method. That is, instead of predicting the curing time based on the absolute values of temperature, slump, air, and water content, the differences between a particular mix and a reference mix were analyzed. A random forest model was developed using the same method as in Example 5, and the results are shown in Figure 14, where the x-axis is the actual curing time and the y-axis is the predicted curing time. Iso-lines are plotted along with the predicted points for the test set. Again, the correlation is evident and is improved with a larger dataset. Similar to Example 5, the prediction model can be used to determine the curing time, and thus the difference in curing times.

[0117] Example 7 The same mix design mixing protocol as in the previous example: 1) Place all of the coarse and fine aggregates into the mixer along with 20% water and an air entraining agent. 2) Mix at high speed for 1 minute. 3) Add the cement and mix again at high speed for 2 minutes. 3) Add the HRWR while continuing to mix for an additional 2 minutes. 4) Stop the mixer and let it sit for 3 minutes. 5) Resume mixing at high speed for 2 minutes. 6) Reduce the speed and mix for 22 minutes to simulate transport to the job site. 7) Remove 0.25 cubic feet of concrete to simulate partial discharge, and 8) Mix for an additional 15 minutes at the loading rate. Three scenarios were compared. 1) Without the addition of Recover® (a hydration retarder). 2) One dosage of Recover® immediately prior to mixing after 0.25 cubic feet of discharge. 3) Three or four gradually increasing dosages (i.e., "dribbled-in") that total one dosage. After mixing, slump, air, strength, and curing time were measured. The curing time was estimated by using the fraction method when analyzing the semi-adiabatic temperature data of the concrete. The time corresponding to a temperature rise that is 21% of the maximum temperature was used for initial curing, and the time corresponding to a temperature rise that is 41% of the maximum temperature was used for final curing (see, for example, http: / / www.nrmcaevents.org / ?nav=download&file=541).

[0118] Two different dosage levels were tested. Within each level, both the split-dose and single-dose had exactly the same total dosage. The first dosage level was tested at 1.0 oz / cwt. In the split-dose scenario, four tests were conducted and there was an average increase of 82 minutes in initial hardening compared to the blend without Recover®. The standard deviation was 24 minutes. In the single-dose scenario, three tests were conducted and there was an average increase of 32 minutes in initial hardening compared to the blend without Recover®. The standard deviation was 27 minutes. Since it was expected that earlier and higher dosages of Recover would provide the greatest delaying effect, it was surprising that the gradually increasing dosage schedule provided a more consistent and greater delaying effect.

[0119] At the 4.73 ounces / cwt dosage, two tests were conducted for each scenario. In the split-dose scenario, the average increase in initial hardening time was 286 minutes, while in the single-dose scenario it was 289 minutes. The standard deviations were 7 minutes and 16 minutes respectively. Thus, at higher dosages, the difference between the two scenarios decreases. Therefore, depending on the dosage required, a gradually increasing schedule or a split-dose schedule may be preferred.

[0120] The embodiments disclosed herein are described herein using a limited number of exemplary embodiments that are not intended to limit the scope of the invention as otherwise described and claimed herein.

Claims

1. 1. A method for regulating delivery of concrete, comprising: (A) providing at least two delivery trucks, each having a mixer drum containing a concrete load and a processor controlled system for monitoring rheology and at least one set time value or range of values ​​of the concrete load in the drum, wherein the processor: i. accessing at least one stored set time value or range of values ​​assigned to a load of concrete in a mixer drum for delivery to a job site; ii. calculating at least one current set time value or range of values ​​for the load based on the monitored hydration over time; iii. comparing said at least one stored cure time value or range of values ​​with said at least one calculated current cure time value or range of values; and (B) adjusting a current set time value(s) or range(s) of values ​​by introducing a set accelerator, set retarder, or mixtures thereof into at least one of the at least two delivery truck concrete loads to perform or modify a sequential placement, finishing, demolding, framing removal, or compressive strength stage of the concrete load poured from the at least two delivery trucks; The method includes:

2. 2. The method of claim 1, wherein in step (A) at least three delivery trucks (more preferably at least six trucks) are provided, each having a mixer drum containing a concrete load and a processor control system for monitoring rheology and monitoring a set time value or range of values ​​of the concrete load in the drum, the processor performing functions (i), (ii) and (iii) to adjust the stored set time value or range of values ​​or the current set time value or range of values ​​of the concrete.

3. The method of claim 1 , wherein both the stored cure time value or range of values ​​and the current cure time value or range of values ​​are adjusted.

4. The method of claim 1 , wherein the stored set time value or range of values ​​is calculated based on factors including an estimated age of the concrete at the time of pouring.

5. 2. The method of claim 1, wherein the set time value or range of values ​​is selected from time values ​​for: (a) starting finishing; (b) completing finishing; (c) removing framework or forms from the concrete; (d) allowing foot or vehicle traffic over the concrete; (e) releasing tensioned cables from jacks (used in prestressed concrete applications); (f) anchoring or grouting post-tensioned cables (for post-tensioned concrete); or (g) pouring more concrete on top of previously poured concrete.

6. The stored set time values ​​or ranges of values ​​accessed or accessed and adjusted by at least one of the delivery truck processor control systems may be determined based on: (a) ticket information provided by a batch plant that supplied the concrete in the truck mixer drum; (b) a supervisor at a job site where concrete is poured from the truck mixer drum; (c) a temperature sensor placed against a surface of or embedded in concrete poured or placed at the job site or another job site; or (d) a processor receiving data signals from a humidity, moisture, and / or temperature sensor; or (e) a processor monitoring another concrete delivery truck having a processor control system for monitoring the rheology and set time value or range of values ​​of the concrete load.

7. 10. The method of claim 1, further comprising the steps of adjusting the at least one stored cure time value or range of values, and providing a report or indication of the adjustment made to the at least one stored cure time value or range of values.

8. 2. The method of claim 1, wherein the current set time value or range of values ​​is compared to a stored set time value or range of values ​​with respect to at least one factor selected from temperature of the concrete, rate of change of temperature of the concrete, batch volume or mix design of the concrete, adjustment of water or chemical admixtures added within the concrete load, rheology, or other property of the concrete.

9. 2. The method of claim 1, wherein at least one of the concrete loads in one of the at least two delivery trucks is returned concrete, and further wherein comparing a stored set time value or range of values ​​to a current set time value or range of values ​​includes taking into account an age of the concrete from the initial batch of the concrete returned from the job site.

10. 2. The method of claim 1, wherein a first concrete load from a first delivery truck is poured into position and a second concrete load from a second delivery truck is poured on top of the first concrete load while the first concrete load is in a plastic state, the first load and the second load having overlapping set time values ​​or ranges of values.

11. 2. The method of claim 1, wherein the stored set time value or range of values ​​for the pre-delivered and placed concrete at the work site is obtained or derived from a data signal generated by at least one sensor in the nozzle, hose, or other conduit of concrete during deposition or spraying of the concrete through the nozzle, hose, or conduit at the work site.

12. 2. The method of claim 1, wherein a portion of at least one of the concrete loads in the delivery truck is poured at a first job site, and within 15 minutes, more preferably within 10 minutes, of the pouring, a dose of set retarder is introduced into the remaining portion of the concrete load in the delivery truck, and the remaining portion including the dose of set retarder is transported by the delivery truck to a second job site and poured into a predetermined location at the second job site.

13. 2. The method of claim 1, wherein at least five (more preferably at least ten) delivery trucks are provided in accordance with step (A) having concrete loads for which set time values ​​or ranges of values ​​are adjusted in accordance with step (B), said adjustment being performed using calculation of set time values ​​or ranges of values ​​based on signal data obtained or derived from at least one sensor for monitoring the hydration over time of concrete placed at the job site.

14. 1. A method for monitoring set time conditions of a plurality of concrete placements, comprising: and operating at least one aerial drone having at least one sensor for monitoring the hydration of the placed concrete over time to obtain a data signal indicative of hydration. moving the concrete around a plurality of concrete placement locations on the job site; comparing the obtained data signal with previously stored data signals to obtain a set time value or range of values ​​that correlates with hydration data over time obtained from at least one sensor; generating a pictorial or map of multiple concrete placement locations along with set time values ​​or ranges of values, or suggested sequence priorities based on set time values ​​or ranges of values, thereby providing placement instructions suitable for sequential processing for (a) starting finishing, (b) completing finishing, (c) removing framework or forms from said concrete, (d) allowing foot or vehicular traffic over said concrete, (e) releasing tensioned cables from jacks, (f) securing or grouting cables after tensioning, or (g) pouring additional concrete on top of previously poured concrete; The method includes:

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